The present invention relates a generally to vehicle moldings, and specifically to a vehicle molding for installation on vehicle roofs.
An automobile roof is typically fixed to the automobile body by welding both sides of a roof panel to a vehicle side panel. However, the welding creates an aesthetically unpleasing weld seam. In order to hide the seam, a roof molding such as that disclosed in Japanese Patent Application No. 2001-300953 is fixed on a groove defined by the welded roof and vehicle side panels.
FIG. 5 illustrates an end of a roof molding 100. The roof molding 100 has an elongate body 110 and a bent end 120. The bent end 120 is formed continuously with the elongate body 110 and is bent at an angle from the elongate body 110. The elongate body 110 has a finished side 111, a base 112 and a lip portion 113. The finished side 111 covers a groove (not shown) of the roof (not shown) and is visible on the exterior of the vehicle. The base 112 is formed on the back side of the finished side 111 and is inserted in the groove. The lip portion 113 is formed on the bottom of the base 112 in order to ensure the stability of the base 112 when inserted into the groove. A metal core is implanted in the base 112 to reinforce the base 112.
FIGS. 6A–6C illustrate the manufacturing process of a roof molding such as that shown in FIG. 5. Initially, as shown in FIG. 6A, a melted resin is extruded by an extruder (not shown), and then cut into predetermined lengths to produce an elongate intermediate product 130 with the finished side 111, the base 112 and the lip portion 113. The metal core 114, which extends along the length of the intermediate product 130, is implanted in the base 112 by a conventional insert molding method. Next, as shown in FIG. 6B, a portion of the base 112 and the lip portion 113 corresponding to the groove formed between the roof interior and exterior panels is cut from an end portion 115 of the intermediate product 130 shown as the hatched portion. Finally, as shown in FIG. 6C, the end portion 115 is heated and pressed by a core mold 141 and a cavity mold 142 to form a bent end 120.
In the roof molding manufactured as discussed above, the pressed end portion 115 is heated at a temperature that is lower than the melting point of the resin to prevent the surface of the roof molding from becoming roughened. Thus, the heating and pressing operation illustrated in FIG. 6C is carried out at a low temperature that creates a stretching tension at the surface of the bent end 120 and an internal shrinkage strain in the bent end 120. Because of the shrinkage strain, the bent end 120 is gradually restored to its elongate shape once the heating and pressing operation is finished.